I've create my own project and server. Everything works fine but within java
files the content assist (ctrl+Space) does not work. However google did not
give me any answer. Within the same source file other featrues work as
intended (ctrl+t finds every type, organize imports works). And of course
the source file is located inside a source folder.

The facet depends on "jst.java" facet [6.0. It does not reuse other facets.
And hopefully it gets initialized correctly (compilation and all the server
stuff works). Do I miss something? Or is there a facet missing? The project
itself currently only contains one source folder and a runtime classpath
container. Resolving this container works too. I am trying to create a
simple java project containg a runtime class path and used by a specialized
application server (no generic stuff).

I did some debugging for many hours (and learned something about the
proposal concepts). The test workspace only enabled jpa proposals and of
course this did not work. Manually enabling java porposals in preference
view worked. And a clean workspace works too. Since I never deactivate this
it is weird. A ghost seems to manipulate my preferences ;-)
But i will not think about it any more :-)